bug#25458: 25.1; tar mode does not handle compressed archives without specific extensions

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: pot@gnu.org,  25458@debbugs.gnu.org
> Date: Fri, 13 May 2022 17:53:15 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > But decompressing means, for most compression types, running an
> > external program on the file.  Or does OP suggest that we link Emacs
> > against libbz2, liblz4, liblzma, etc. to have these decompression
> > methods available in core?
> 
> No, it would work just like when you read a tar.gz file -- we use
> external decompressors for that, too, even if we then parse the
> resulting tar file ourselves. 

Then I guess I don't understand what is the problem we are asked to
fix here.  Francesco, can you explain?